Locking fasteners and locking fastener assemblies are used to prevent loosening of a threaded fastener in a fastener joint. There are many types of threaded joints in which loosening of a fastener is undesirable. One example to which the principles of the present invention may be applied is an axle assembly of a vehicle, including automobiles, trucks, trailers or other transportation devices.
In a typical axle assembly, axle bearings are supported between an axle or spindle and a wheel hub or spindle support to permit rotation of a vehicle wheel. An axle bearing nut is used to hold the components together. Usually, the axle bearing assembly is encased with grease and sealed so that outside contaminates, which can lead to premature bearing wear and failure, cannot enter the bearing assembly. Moreover, in order to prevent premature bearing failure, the nut must be installed properly and tightened to the proper torque to avoid excessive axial bearing load or, alternatively, excessive free play. In addition, after assembly, it is important to prevent loosening of the axle bearing nut to avoid bearing failure or even the dangerous loss of a wheel.
A conventional axle assembly includes a spindle with male threads having an axially extending slot. In order to provide for a locking nut that would mate with the spindle, U.S. Pat. No. 6,290,442, also owned by the current assignee, discloses a highly adjustable locking fastener assembly that includes a washer and a nut. The washer includes a multitude of notches on the periphery thereof and a tab received in the axially extending slot of a spindle to permit the washer to move axially, yet prevent the washer from rotating. The nut of this system has a flange that contains a plurality of unequally spaced openings through which bolts would be placed to engaged the notches on the washer, thereby preventing relative rotation between the washer and the nut.
While this prior locking assembly provided an installer with a high number of adjustment positions, it did not allow for easy sight alignment between the holes in the flange of the nut and the notches in the washer. As a result, if an installer was not careful to align the bolt hole on the nut and the notch on the washer, part of the bolt could scrape against the sides of the washer notches, causing metal shaving to fall into the sealed bearing assembly. Such metal shavings could lead to excessive bearing wear. Accordingly, there is a need for an adjustable locking fastener assembly for a threaded joint having a nut and a washer that allows for easy visual alignment of connecting members on the nut and washer.
Other needs will become apparent upon a further reading of the following detailed description taken in conjunction with the drawings.